WO2019025307A1

WO2019025307A1 - Metal-plastic plain-bearing composite material and plain bearing element produced therefrom

Info

Publication number: WO2019025307A1
Application number: PCT/EP2018/070407
Authority: WO
Inventors: Riitta Taipalus; Rolf Reinicke
Original assignee: Ks Gleitlager Gmbh
Priority date: 2017-08-04
Filing date: 2018-07-27
Publication date: 2019-02-07
Also published as: EP3661742A1; DE102017117736B4; DE102017117736A1; US20210317874A1; US11946507B2; EP3661742B1

Abstract

The invention relates to a metal-plastic plain-bearing composite material (2), in particular for producing plain bearing elements for lubricated applications, comprising a metal support layer (4), in particular of steel or bronze, and comprising a sliding layer (12) of a sliding material (8) of a matrix-forming PTFE polymer base with fillers that improve the tribological properties, said sliding layer being in sliding contact with a sliding partner, characterized in that the sliding material contains, as fillers, 1-15 vol% barium sulfate, 5-20 vol% aramide, 1-10 vol% polyimide, 1-15 vol% fluorothermoplastic excluding PTFE. The invention further relates to a plain-bearing composite material and to a plain bearing element.

Description

Title: Metal-plastic sliding bearing composite material and slide bearing element produced therefrom

description

The invention relates to a metal / plastic sliding bearing composite material, in particular for the production of sliding bearing elements for lubricated applications, with a metallic support layer, in particular made of steel or bronze, and with an in sliding contact with a

Gleitpartner stationary sliding layer of a sliding material of a matrix-forming PTFE polymer base with the

tribological properties of improving fillers. In the prior art are a variety of

Sliding materials are known which are based for example on PTFE and use different fillers. For example, DE 10 2011 077 008 A1 is a

Plain bearing composite material based on PTFE, wherein fillers comprising thermoplastics and / or thermosets and other tribologically active substances together in compounded form in the polymer base of

Sliding layer material present.

Furthermore, EP 2 316 707 A1 and EP

1 647 574 AI a sliding bearing composite material based on PTFE with barium sulfate, phosphate and an amount of 0.1 to 2% metal sulfide known.

EP 0 938 970 B1 describes a

Laminated material with a matrix of PTFE or PTFE in combination with ETFE, in which fillers are embedded. As a filler, in particular a powdered

Aramid can be used. The aramid should have a proportion of 0.5 to 10% by volume, the proportion of further fillers being 9.5 to 44.5% by volume and the proportion of the polymer base is 55 to 90% by volume. In addition, polyimides can be used as additional fillers.

Finally, DE 198 08 540 B4 describes a

PTFE-based layer composite with 10 to 50% by volume of a powdered aramid. In addition, more can Fillers, e.g. As polyimide, be used. The material contains, according to a variant, other fluorothermoplasts. Despite the large number of known sliding materials, there is still a need for lubricating materials, in particular as a bearing material for applications operated under high-load lubrication.

Especially at slow reversing

Rotational movements since then there is the problem that in the known in the prior art metal / plastic sliding bearing composite materials either too high

Wear or excessive friction is given. A metal / plastic composite bearing material

To provide that solves this problem, is an object of the invention.

The object is achieved by a metal / plastic sliding bearing composite with a sliding layer of a sliding material of a matrix-forming PTFE polymer base with the tribological properties

improving fillers, characterized in that the sliding material as fillers

1-15% by volume of barium sulfate,

5-20% by volume of aramid,

1-10 vol.% Polyimide,

1-15 vol.% Fluorothermoplastics except PTFE,

contains. The volume fractions of the fillers are based on the sliding material.

Such metal / plastic friction bearing composite materials show improved behavior in heavily loaded, lubricated applications with low

Sliding speeds. In such applications, it is usually slow, reversing rotational movements, such as those in

Seat adjusters are to be found. In addition, hinges continue to be considered as applications. The intended use is preferably in motor remote applications in the field of automobiles. Barium sulphate serves the strength gain of the

Sliding material, wherein polyimide and aramid the

Increase wear resistance. The addition of one or more fluorothermoplastics except PTFE improves the adhesion and integration of all other fillers in the PTFE polymer base and thus serves as a coupling agent.

Particularly preferred is a sliding material with

following fillers:

1 to 10% by volume of barium sulfate

10 to 15% by volume of aramid

1 to 10% by volume, in particular 1 to 8% by volume of polyimide 1 to 10% by volume, in particular 1 to 8% by volume

Fluorothermoplastic except PTFE. Further particularly preferred is a sliding material, as fillers

3 to 7% by volume of barium sulfate,

10 to 13% by volume of aramid,

3 to 8 vol.% Polyimide,

- Contains 3 to 7 vol .-% fluorothermoplastic except PTFE. It is particularly preferred if the

Fluorothermoplastics from the group FEP, PFA or MFA or combinations thereof are selected. With these

Fluorothermoplastics is a particularly preferred

Modification of the PTFE polymer base achieved.

It is particularly advantageous if the aramid and / or the polyimide are incorporated as a powdery additive. The particulate aramid and / or polyimide are incorporated into the matrix. It is further preferred if the particle size of the aramid has a D50 value of from 30 .mu.m to 90 .mu.m for aramid. The diameter of the

Aramid particles should not exceed 200 ym. The D50 value of the aramid particles is determined according to the measurement method ISO 13320, Static Laser Scattering Light Analysis. The D50 value of the particle size of the polyimide should preferably be from 1 μm to 20 μm, and is determined by the same method. For the fluorothermoplastics, preferably FEP, the D50 value for the particle size should be 20 μm to 80 μm, likewise determined according to ISO 13320.

For the further filler barium sulfate is the

preferred D50 particle size at 0.2 ym to 1.4 ym. The determination is carried out according to DIN 66111 and here on the particle size analysis by sedimentation. In this case, a very low value for barium sulfate is particularly preferred since this makes the strength of the sliding material positive

affected. The indication D50 refers to mass percentages.

Under a powder is thereby delimited, e.g. for a fiber, means a particle having a shape in which, on the basis of extensions in three axes, the longest extension is not more than five times as long as the shortest extension, preferably not more than three times and more preferably not more than two times as long.

In addition to a powder form, aramid and / or polyimide may also be fibrous and used according to the invention. For the fiber shape, a length to diameter ratio is greater than 5: 1.

Preference is given to ratios of the proportions by volume of aramid to polyimide of from 15: 1 to 2: 1 and preferably from 10: 1 to 3: 1. Preferred ratios of the volume fractions of barium sulfate to one or more fluorothermoplasts are 3: 1 to 1: 3 and preferably 2: 1 to 1: 2.

The addition of fluorothermoplastics to the PTFE polymer base modifies the PTFE in a manner that improves the adhesion of all the components of the slip material to one another, thereby improving wear resistance. It is particularly preferred that it is a lead-free sliding material. This allows important environmental aspects to be taken into account. The sliding material is according to the invention part of a

Metal / plastic-bonded bearing composite material, in particular for producing sliding bearing elements for lubricated applications with a metallic support layer,

in particular of steel or bronze, and a sliding layer in sliding contact with a sliding partner. Such applications are grease-lubricated applications that are slowly rotating or reversing, and that have a high load applied to a slow sliding motion. such

Slide bearing composite materials are used in the automotive sector,

For example, with hinges or

Seat adjusters, used.

It is particularly preferred if the sliding material in a formed on the metallic support layer porous support layer, in particular in a

metallic particles sintered backing layer is anchored. Alternatively, the sliding material can be anchored directly to a microstructured surface of the metallic support layer.

Further alternatively, it can be provided that the

Sliding material by means of an adhesive layer on the applied metallic support layer, preferably adhered.

As a further possible variant, it is also possible to apply the sliding material according to the invention to a metal mesh or mesh, for example in the form of an expanded metal. These can for example consist of a

Bronze material exist. The metal mesh or lattice, in particular the expanded metal can as support or

Carrier layer can be used.

The preparation of the sliding material can in

done in different ways. For example, a PTFE dispersion to which the fillers are added may be precipitated, thereby separating the PTFE polymer base with the fillers from the water. This creates a kind of paste. This paste can be applied to the porous carrier

are applied and rolled into it and is then sintered. The material is then in strips

cut and the resulting boards are wound into trays or jacks.

Alternatively, it is also possible, especially for thicker layers, to mix PTFE powder and fillers with each other. The material is then filled into a substantially cylindrical shape and pressure sintered. This results in a shaped body from which a type of film can be obtained by peeling. This film can then be applied to the support layer, in particular glued. By using a sliding bearing composite material with a sliding layer according to the type described above, the advantage is achieved that for the applications described above, the properties friction and wear in a positive manner, ie in the direction of low wear and low friction, can be influenced.

The sliding bearing composite material is furthermore particularly designed so that the layer thickness of the metallic support layer is 0.15 to 5 mm and the layer thickness of the porous support layer, if provided, at least 0.05 mm, in particular at least 0.1 mm, in particular at least 0.2 mm and at most 0.6 mm, in particular at most 0.5 mm, and in that the supernatant of the sliding material over the porous support layer is at least 10 μm, in particular at least 20 μm and in particular at least 30 μm, in particular

is at least 50 ym, in particular at least 100 ym and in particular at most 600 ym, in particular at most 500 ym, in particular at most 400 ym. Preferably, the supernatant is rolled into the material

Sliding materials based on pastes 5 - 80 ym, preferably 10 to 50 ym and in the case of film-like lubricating materials 100 - 400 ym and preferably 150 to 300 ym. In addition, protection is claimed for a method of producing a sliding material for a wearer

in particular of steel or bronze, and one in sliding Contact with a sliding partner sliding layer of a sliding material based on a PTFE polymer base, wherein the PTFE polymer base, the tribological

Properties improving fillers are added in the following proportions and particle sizes:

1-15% by volume of barium sulfate,

5-20% by volume of aramid,

1-10 vol.% Polyimide

1-15 vol.% Fluorothermoplastic except PTFE, and wherein the particles of the added substantially spherical filler particles have a D50 value for

Barium sulfate of 0.2-1.4 ym

- Aramid of 30 - 90 ym

Polyimide of 1-20 ym

Fluorothermoplastic except PTFE from 20 to 80 ym have. For aramid, the value Dmax is preferably 200 ym.

The aramid used is preferably poly-paraphenyleneterephthalamide and as fluorothermoplast FEP and here

Copolymer of hexafluoropropylene and tetrafluoroethylene. Details, features and advantages of the invention will be apparent from the appended claims and from

diagrammatic representation and subsequent description of preferred embodiments of the invention. In the drawing show: Figure 1 is a schematic sectional view of a sliding bearing composite material according to the invention; FIG. 2 shows measurement results for the wear resistance of

Comparative materials and the material according to the invention;

FIG. 3 shows measurement results for the coefficient of friction of FIG

Comparative materials and the invention

Material; and

FIG. 1 shows a sectional view according to the invention of an overall reference numeral 2

Bearing composite material. This includes one

metallic support layer 4, preferably and typically of steel. This is exemplified and preferred

Case shown a porous support layer 6 in the form of sintered bronze particles of an exemplary

Composition sintered Cu90SnlO. In these

Three-dimensionally porous carrier layer 6 is a

Sliding material 8 applied from a matrix-forming PTFE polymer base, in such a way that the sliding material 8 forms a supernatant 10 on the uppermost particles of the carrier layer 6. The sliding material 8 thus forms a sliding layer 12 facing the sliding partner.

According to the invention, the sliding material comprises 1 to 15% by volume of barium sulfate, 5 to 20% by volume of aramid, 1 to 10% by volume.

Polyimide, 1 to 15% by volume of fluorothermoplastic, with the remainder formed by the PTFE polymer base. The fillers improve the tribological properties. In addition to barium sulfate, which serves for strength, and is preferably present in fine particles, the polyimide (s) and the at least one aramid serve to improve the

Wear resistance of the material. The at least one fluorothermoplastic acts together with the PTFE and modifies the PTFE so that the fillers better

be involved.

It would also be conceivable that the sliding material 8 is not anchored in a separately applied carrier layer 6, but in a microstructured surface of the metallic support layer 4 or is glued to the metallic support layer 4 by means of an adhesive bonding layer.

Bushings of the construction according to Figure 1 to be tested were made from a sliding bearing composite, i. brought in a bending roll on cylindrical socket with a butt joint. The overlay has the design mentioned in the following table. The

Testing of the tribological properties was carried out with the following test parameters. The bearings were in a grease-lubricated barrel with reversing

Rotational movement tested at medium speed of 0.03 m / s. Here, the plain bearing rotates around one

Against runners. The force is introduced by a spring preload and thereby the sliding bearing on the

Pressed counter-body. Test parameters:

The composition of the sliding material is in the

shown in the following table. The data are in each case in% by volume based on the sliding material.

The reference 1 was used as a comparative sample

used. The references 1, 2 and 3 are sliding materials of the Applicant, as the state of

Technology are already known. Examples 1 to 5 correspond to comparative examples according to the invention, in which case one or more of the envisaged fillers according to the invention are not provided. Example 6 is an example according to the invention. In this case, the fillers according to the following specification with respect to

Particle sizes used:

FIG. 2 shows the relative wear with reference to reference 1. It can be seen that reference 1 is 100%, reference 2 being about 20% worse

cuts. Reference 3, which includes aramid fibers, shows even worse wear values. The wear then improves in Examples 1 to 6 and reaches its lowest and thus best value in the inventive example (Example 6).

FIG. 3 shows the relative coefficient of friction, also here relative to 100% at reference 1. Here too, it can be seen that the relative coefficient of friction for example 6 according to the invention is lowest and thus the best sliding properties are achieved.

Claims

claims

Metal / plastic composite bearing material (2), in particular for producing sliding bearing elements for lubricated applications, having a metallic supporting layer (4), in particular made of steel or bronze, and having an in sliding contact with a

Gleitpartner stationary sliding layer (12) of a sliding material (8) of a matrix-forming PTFE polymer base with the tribological properties of improving fillers, characterized in that the sliding material as fillers

1-15% by volume of barium sulfate,

5-20% by volume of aramid,

1-10 vol.% Polyimide,

1-15 vol.% Fluorothermoplastics except PTFE,

contains.

Metal / synthetic material sliding bearing composite material according to claim 1, characterized in that the

Sliding material as fillers

1-10% by volume of barium sulfate,

10-15 vol.% Aramid,

1-10 vol.%, Especially 1-8 vol.% Polyimide,

1-10 vol .-%, in particular 1-8 vol .-% fluorothermoplastic except PTFE,

contains. Metal / synthetic material sliding bearing composite material according to claim 1 or 2, characterized in that the sliding material as fillers

3-7% by volume of barium sulfate,

10-13% by volume aramid,

3-8 vol.% Polyimide,

3-7% by volume of fluorothermoplastic except PTFE,

contains.

Metal / synthetic material sliding bearing composite material according to one of the preceding claims, characterized

in that the fluorothermoplastic is selected from the group FEP, PFA or MFA or combinations thereof.

in that the aramid and / or the polyimide is powdery and / or fibrous.

in that the ratio of the proportions by volume of the fillers aramid to polyimide is 15: 1 to 2: 1 and preferably 10: 1 to 3: 1.

characterized in that the ratio of the volume fractions of the fillers barium sulfate to fluorothermoplastic except PTFE 3: 1 to 1: 3 and preferably 2: 1 to 1: 2.

8. Metal / plastic sliding bearing composite material according to one of the preceding claims, characterized

in that the substantially spherical filler particles have a D50 value for barium sulfate of 0.2 μm to 1.4 μm, for aramid 30 μm to 90 μm, for

Polyimide 1 μιη to 20 ym, for fluorothermoplastic except PTFE 20 μιη to 80 ym have.

9. metal / plastic sliding bearing composite according to

one of the preceding claims, characterized

characterized in that the maximum particle size for

Aramid Dmax <200 ym.

10. Metal / plastic sliding bearing composite according to

one of the preceding claims, characterized

characterized in that the sliding material is lead-free. 11. Metal / plastic sliding bearing composite according to

one of the preceding claims, characterized

in that the sliding material (8) is formed in a porous carrier layer (6) formed on the metallic support layer (4), in particular in a carrier layer sintered from metallic particles

(6) or anchored in an expanded metal layer or in a fabric layer.

12. Metal / plastic sliding bearing composite according to

one of the preceding claims, characterized

in that the sliding material (8) is anchored to a microstructured surface of the metallic support layer (4).

13. metal / plastic sliding bearing composite material according to one of the preceding claims, characterized

in that the sliding material (8) is applied, preferably glued, to the metallic support layer (4) by means of an adhesion-promoting layer.

14. Metal / plastic sliding bearing composite material after

one of the preceding claims, that the

Layer thickness of the metallic support layer (4) 0.15 - 5 mm is that the layer thickness of the porous

Carrier layer (6) is at least 0.05 mm, in particular at least 0.1 mm, in particular at least 0.2 mm and at most 0.6 mm, in particular at most 0.5 mm, and that the supernatant (10) of

Sliding material (8) over the porous support layer (6) at least 10 ym, especially at least 20 ym, in particular at least 30 ym, especially at least 50 ym, especially at least 100 ym and at most 600 ym, in particular at most 500 ym, in particular at most 400 ym.

15. plain bearing element made of a

Slide bearing composite material (2) according to one of

preceding claims.

16. plain bearing element according to claim 15, characterized

characterized in that it is a sliding strip, a

Sliding shoe, or sliding pad or one

Slide bearing shell or plain bearing bush or

Sliding bearing collar is. A method of producing a sliding material for a metal / plastic composite bearing material according to any one of claims 1 to 14, wherein tribological properties improving fillers are added to the PTFE polymer base of the sliding material in the following proportions and particle sizes:

1-15% by volume of barium sulfate,

5-20% by volume of aramid,

1-10 vol.% Polyimide,

1-15 vol .-% fluorothermoplast except PTFE, and wherein the particle sizes of the added substantially spherical filler particles has a D50 value for barium sulfate of 0.2 μιη to 1.4 ym,

Aramid 30 μιη to 90 ym,

Polyimide 1 μη to 20 ym,

Fluorothermoplast 20 μιη to 80 ym,

having .

A method according to claim 17, characterized in that as aramid a powder with maximum

Particle diameter Dmax <200 ym is used.